html source code function to filter html code under php to improve program security

The following is a function to filter HTML code:

Copy code The code is as follows:

function ihtmlspecialchars($string) {
if(is_array($string)) {
foreach($string as $key => $val) {
$string[$key] = ihtmlspecialchars($val);
}
} else {
$string = preg_replace('/&((#(d{3,5}|x[a-fA- F0-9]{4})|[a-zA-Z][a-z0-9]{2,5});)/', '&\1',
str_replace(array('&', ' "', '<', '>'), array('&', '"', '<', '>'), $string));
}
return $string;
}

Copy code The code is as follows:

function htmlEncode($string) {
$string=trim($string);
$string=str_replace("&", "&",$string);
$string=str_replace("'","'",$string);
$string=str_replace("&","&",$string);
$string=str_replace( """,""",$string);
$string=str_replace(""",""",$string);
$string=str_replace("<","<",$string);
$string=str_replace("<","<",$string);
$string=str_replace(">",">",$string);
$string=str_replace(">" ,">",$string);
$string=str_replace(" "," ",$string);
$string=nl2br($string);
return $string;
}

The above introduces the html source code and the function of filtering html code under PHP to improve program security, including the content of html source code. I hope it will be helpful to friends who are interested in PHP tutorials.